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GCN Circular 307

GRB 990123, optical monitoring
1999-05-10T19:04:54Z (25 years ago)
Arne A. Henden at USNO/USRA <>
The U. S. Naval Observatory GRB Team (A. Henden (USRA/USNO),
R. Stone, F. Vrba, C. Luginbuhl, B. Canzian, J. Munn, S. Levine,
H. Guetter (USNO)) report:

We have been monitoring the Optical Transient position
for GRB 990123 with the USNOFS 0.2-m FASTT system (Stone et.
al. 1996, AJ 111, 1721).
As this is a converted transit telescope, we were not
able to begin observations until the field started to
transit in darkness.  However, we have single-epoch
data for the following nights (yymmdd UT):
    990225 990302 990303 990304 990305
    990309 990310 990316 990320 990321
    990322 990323 990329 990330 990331
Typical limiting magnitude at R was 18.3.  We saw no
recurrence of the transient during this period.

We also report single-epoch JHK measures (with the USNO
1.55-m telescope and infrared camera) on 990202, and
J measures on 990328 and 990427.  Typical limiting magnitude at
J was 17.5.  No recurrence was seen.
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